1. Field
The present disclosure relates to a process of making a bearing using an ultrasonic nano crystal surface modification technology.
2. Discussion of the Related Art
A bearing refers to a mechanical element which fixes a shaft of a machine, which is rotating, in a predetermined position and rotates the shaft in support of a weight of the shaft and load imposed on the shaft. Since the bearing is rubbed, bent, twisted, sealed, or compressed due to high load and a high speed, the bearing requires high precision and strength. Therefore, various specific processing methods have been developed to increase life-spans and reduce friction losses of bearings.
Coating using physical vapor deposition (PVD) or chemical vapor deposition or ion implanting is used as a specific processing method for improving hardness of a bearing to reduce wear rate or a relative friction coefficient of the bearing. However, in such a surface hardening processing method, it is difficult to evenly process a surface of a bearing. If the bearing rolls, the bearing is peeled.
Shot peening, laser shot peening, deep rolling, ultrasonic shot peening, water jet peening, etc. are used to apply compressive residual stress to a surface of a bearing in order to remove a directivity of mechanical processing of the bearing and improve a fatigue life of the bearing.
The foregoing discussion is to provide general background information, and does not constitute an admission of prior art.